In modern electronic engineering for computer and communication systems there is an increasing need for higher frequency devices and channels to handle signals with frequencies of 10.sup.8 Hz or higher. Optical waveguides and fibers are being given serious consideration as a response to that need.
Optical waveguides and fibers guide information-carrying laser beams at optical frequencies. The useable range of light wave lengths is much broader than the visible wave lengths, 4,000-7,000 Angstrom units. Useable optical wave lengths extend substantially into the ultra-violet range below 4,000 Angstroms and into the infra-red range above 7,000 Angstroms.
There are two major kinds of optical waveguides as follows.